X (formerly Twitter) has one of the oldest and most established OG-username markets of any platform, dating back to the site's earliest years. Because it's been around since 2006, "OG" here often specifically means an account from the platform's first several years, which is a genuinely long history compared to newer apps.
Single-word and short handles on X are frequently sought by brands and public figures, not just collectors — that extra layer of demand (beyond the trading community itself) is part of why some of the highest publicly reported username sale prices anywhere have involved X/Twitter handles.
Open the vault, pick a listed username, and DM the contact handle shown on the site to arrange payment — there's no cart/checkout, it's a direct conversation with the seller.
Crypto-only. See the Terms of Service for the full payment and delivery policy, including the sale-finality and 72-hour issue window.